Congenital cutaneous mastocytosis

This code represents a rare, congenital form of mastocytosis characterized by an abnormal proliferation of mast cells in the skin, present at birth or shortly thereafter. It manifests as various skin lesions, such as macules, papules, plaques, or nodules, which may urticate when rubbed (Darier's sign).

Use this code for patients diagnosed with cutaneous mastocytosis that is explicitly documented as congenital in origin. This diagnosis is typically made in neonates or infants presenting with characteristic skin lesions and confirmed by biopsy showing increased mast cells. Documentation should clearly state the congenital nature of the condition.

• Differentiate carefully from other forms of mastocytosis; ensure the "congenital" aspect is clearly documented.
• Review the "Excludes1" notes to avoid incorrect co-coding with non-congenital or systemic forms of mastocytosis.
• Confirm the onset of the condition is at birth or in the newborn period to support the "congenital" designation.